Changing the air filter should be part of any major tune-up, but if you drive on dirt roads or in other dusty conditions, you will need to replace it more frequently. On most cars, this is a fairly simple procedure.
Pop the hood and find the air-filter housing. It will be either square (on fuel-injected engines) or round (on older carbureted engines) and about 12 inches (30 cm) in diameter.
Use a Phillips screwdriver to remove the screws or clamps that hold on the top of the housing.
Take out the old air filter (see illustration) and clean any dirt and debris from the housing with a clean rag.
Put the new air filter in.
Screw or clamp the lid of the air-filter housing back on.